Rewrite libdexfile C API to follow NDK guidelines better.

Bug: 123517037
Bug: 145347927
Test: test-art-host-gtest-art_libdexfile_support_tests64
Test: test-art-host-gtest-art_libdexfile_external_tests64
Change-Id: I9673872585456937d2f54abb63e3dbd8aad4e9ad
11 files changed